Motor skills and sport skills are learned by frequent repetition of proper technique. Many people have trouble reaching their full physical potential because either they are not taught proper technique (unlearning “wrong” technique is a challenge), or they become bored with the repetition (practice) process that is required to master the technique, sometimes referred to as burning the technique into “muscle memory.”
In addition, overall participation in physical activity has been declining in the population. This creates a wide range of individual and societal concerns—from obesity to adult-onset diabetes in children. Children are increasingly involved in technology-enabled “screen time”—including watching television and playing computer games. Screen time is often excessive for children because it is so engaging. This contributes to a sedentary lifestyle.
In order to reverse this decline in physical activity within the population, particularly among children, it is desired to provide a system (1) to aid participants in learning and mastering motor skills, and (2) to apply the engaging elements of technology for the positive purpose of promoting physical activity. More specifically, it is desired to promote repetition (and practice) with ongoing, immediate, and engaging feedback.
Various systems have been developed which aim to achieve these goals by providing a simulated sports environment, such as, in particular, by simulating various aspects of baseball (e.g., simulated hitting and pitching systems) and golf.
The trajectory of the struck ball is determined in some golf simulators by measuring parameters of the ball's impact with a surface. In these golf simulation systems, the essential element is a contact surface which allows a system to capture data at the moment of impact. Such a surface usually is equipped with electromechanical or photocell sensors. When a surface impacts with a ball, data captured by the sensors is connected to electrical circuits for analysis. Examples are U.S. Pat. Nos. 4,767,121, 4,086,630, 3,598,976, 3,508,440 and 3,091,466.
However, the electromechanical nature of a contact surface makes it prone to failure and to miscalibration. Frequent physical impacts on the surface tend to damage the sensors, and failure or miscalibration of a single sensor in an array of sensors covering the surface can seriously degrade system accuracy. Abnormalities in a stretched contact surface, such as those produced by high speed impacts, also can produce results that are misleading. Furthermore, the applications of an impact sensing system are limited. Limitations include the requirement to fix the source of the ball at a predetermined distance, limited target area, and insensitivity to soft impacts.
Another trajectory determination technique used in golf simulators is based on microphones sensing the sounds of both a club-to-ball contact and a surface-to-ball contact. With this technique, microphones are placed in four or more locations around the surface so that their combined inputs can measure the point at which the ball surface is hit. Based on the speed of sound, the relative timing of audio events at each microphone provide enough data to allow a computer to derive ball speed and trajectory. This approach may be less prone to electromechanical failure, but it still has its limitations. The limitations of an audio system include the need for at least three channels (having four is preferred), relative insensitivity to soft (low speed) impacts and no ability at all to be used when an object is not struck (e.g., there is substantially no sound created when an object is thrown), and sensitivity to other noise sources.
Some golf simulators also calculate ball spin by reflecting a laser beam off a mirror located on a special golf ball designed specifically for that purpose. The ball must be placed in a particular position prior to being hit with the mirror facing a laser and receiver array. The laser beam's reflection is sensed by a receiver array, and on impact, the motion of the beam is used to determine ball spin. This technology provides data which augments the basic data of speed and trajectory. However, it also requires the use of a special ball and additional equipment.
In another, more recently developed type of system, which is disclosed in U.S. Pat. No. 5,768,151, a computerized system determines the trajectory of an object based upon video images captured by cameras at two fixed viewpoints. Two video cameras are arranged so that each will contain the anticipated trajectory of an object within its field of view. The video cameras are synchronized and have shutter speeds slow enough to yield an image of the object containing a blur due to the object's motion. An audio or an optical trigger, derived either from the event causing object motion or from the object itself, causes at least two images to be captured in digital frame buffers in a computer. Software in the computer accesses each of the digital frame buffers and subtracts the background image to isolate the blurred object. A two-dimensional projection of the object's trajectory is derived for each frame buffer image. The two dimensional trajectories are combined to determine a three dimensional trajectory.
While each of the above-described systems may provide an accurate sports simulation to some degree, they are generally more concerned with providing a highly accurate measurement of the velocity, direction, spin, etc. of a thrown or hit ball than they are with providing an environment that will engage participants, particularly children, for frequent repetitions of an activity. This deficiency of the prior art systems leads to two major disadvantages associated therewith: (1) the systems do not effectively promote long term physical activity, particularly among children, and (2) the systems are relatively complex, and therefore costly to produce and maintain, and are prone to failure.
What is desired, therefore, is a system for promoting physical activity which aids participants in learning and mastering motor skills, which promotes repetition with ongoing, immediate, and engaging feedback, which is relatively not costly to produce and maintain, which accurately senses the impact of an object with a surface, which is not prone to failure and/or miscalibration, and which can be used in situations where an object being tracked is not struck with a bat, club, etc.